If you define a libvirt virtual network with one or more IP addresses,
it starts up an instance of dnsmasq. It's always been possible to
avoid dnsmasq's dhcp server (simply don't include a <dhcp> element),
but until now it wasn't possible to avoid having the DNS server
listening; even if the network has no <dns> element, it is started
using default settings.
This patch adds a new attribute to <dns>: enable='yes|no'. For
backward compatibility, it defaults to 'yes', but if you don't want a
DNS server created for the network, you can simply add:
<dns enable='no'/>
to the network configuration, and next time the network is started
there will be no dns server created (if there is dhcp configuration,
dnsmasq will be started with "port=0" which disables the DNS server;
if there is no dhcp configuration, dnsmasq won't be started at all).
The new forward mode 'open' is just like mode='route', except that no
firewall rules are added to assure that any traffic does or doesn't
pass. It is assumed that either they aren't necessary, or they will be
setup outside the scope of libvirt.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=846810
==18324== 32 bytes in 1 blocks are still reachable in loss record 41 of 114
==18324== at 0x4C2C070: calloc (vg_replace_malloc.c:623)
==18324== by 0x4EA479B: virAlloc (viralloc.c:144)
==18324== by 0x4EA674A: virBitmapNewQuiet (virbitmap.c:77)
==18324== by 0x4EA67F7: virBitmapNew (virbitmap.c:106)
==18324== by 0x4EC777D: dnsmasqCapsNewEmpty (virdnsmasq.c:801)
==18324== by 0x4EC781B: dnsmasqCapsNewFromBuffer (virdnsmasq.c:815)
==18324== by 0x407CF4: mymain (networkxml2conftest.c:99)
==18324== by 0x409CF0: virTestMain (testutils.c:982)
==18324== by 0x4080EA: main (networkxml2conftest.c:136)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
dnsmasq conf file contents needs to have quotes escaped for it to
work. Because of this, the network-create/start for a network with
quotes in the name fails. The patch escapes strings for the entries
that go into the conf file.
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.vnet.ibm.com>
So far it's just a structure which happens to have 'Obj' in its
name, but otherwise it not related to virObject at all. No
reference counting, not virObjectLock(), nothing.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This adds a new "localOnly" attribute on the domain element of the
network xml. With this set to "yes", DNS requests under that domain
will only be resolved by libvirt's dnsmasq, never forwarded upstream.
This was how it worked before commit f69a6b987d, and I found that
functionality useful. For example, I have my host's NetworkManager
dnsmasq configured to forward that domain to libvirt's dnsmasq, so I can
easily resolve guest names from outside. But if libvirt's dnsmasq
doesn't know a name and forwards it to the host, I'd get an endless
forwarding loop. Now I can set localOnly="yes" to prevent the loop.
Signed-off-by: Josh Stone <jistone@redhat.com>
Commit a1cbe4b5 added a check for spaces around assignments and this
patch extends it to checks for spaces around '=='. One exception is
virAssertCmpInt where comma after '==' is acceptable (since it is a
macro and '==' is its argument).
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
The test case average timing code has not been used by any test
case ever. Delete it to remove complexity.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Useful to set custom forwarders instead of using the contents of
/etc/resolv.conf. It helps me to setup dnsmasq as local nameserver to
resolve VM domain names from domain 0, when domain option is used.
Signed-off-by: Diego Woitasen <diego.woitasen@vhgroup.net>
Signed-off-by: Eric Blake <eblake@redhat.com>
This resolves the issue that prompted the filing of
https://bugzilla.redhat.com/show_bug.cgi?id=928638
(although the request there is for something much larger and more
general than this patch).
commit f3868259ca disabled the
forwarding to upstream DNS servers of unresolved DNS requests for
names that had no domain, but were just simple host names (no "."
character anywhere in the name). While this behavior is frowned upon
by DNS root servers (that's why it was changed in libvirt), it is
convenient in some cases, and since dnsmasq can be configured to allow
it, it must not be strictly forbidden.
This patch restores the old behavior, but since it is usually
undesirable, restoring it requires specification of a new option in
the network config. Adding the attribute "forwardPlainNames='yes'" to
the <dns> elemnt does the trick - when that attribute is added to a
network config, any simple hostnames that can't be resolved by the
network's dnsmasq instance will be forwarded to the DNS servers listed
in the host's /etc/resolv.conf for an attempt at resolution (just as
any FQDN would be forwarded).
When that attribute *isn't* specified, unresolved simple names will
*not* be forwarded to the upstream DNS server - this is the default
behavior.
The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.
Way back when I started making changes for Coverity messages my first set
were to a bunch of CHECKED_RETURN errors. In particular virAsprintf() had
a few callers that Coverity noted didn't check their return (although some
did check if the buffer being printed to was NULL or not).
It was suggested at the time as a further patch an ATTRIBUTE_RETURN_CHECK
should be added to virAsprintf(), see:
https://www.redhat.com/archives/libvir-list/2013-January/msg00120.html
This patch does that and fixes a few more instances not found by Coverity
that failed the check.
This patch changes how parameters are passed to dnsmasq. Instead of
being on the command line, the parameters are put into a file (one
parameter per line) and a commandline --conf-file= specifies the
location of the file. The file is located in the same directory as
the leases file.
Putting the dnsmasq parameters into a configuration file
allows them to be examined and more easily understood than
examining the command lines displayed by "ps ax". This is
especially true when a number of networks have been started.
When the use of dnsmasq was originally done, the required command line
was simple, but it has gotten more complicated over time and will
likely become even more complicated in the future.
Note: The test conf files have all been renamed .conf instead of
.argv, and tests/networkxml2xmlargvdata was moved to
tests/networkxml2xmlconfdata.
